1. Field of the Invention
The present invention relates to a terminal-modified imide oligomer composition. More particularly, the present invention relates to a composition comprising a terminal-modified aromatic imide oligomer and an unsaturated aromatic imide compound and useful for forming fiber-reinforced resinous articles having an excellent mechanical strength, modulus of elasticity and heat-resistance.
2. Description of the Related Art
It is known that polyimide resin has a superior heat-resistance and mechanical properties, and thus is useful as a matrix resinous material for shaped resinous articles and fiber-reinforced composite resinous articles.
Recently, Japanese Unexamined Patent Publication Nos. 59-167,569, 60-250,030, 60-260,624, 60-260,625, 61-247,733 and 62-29,584 disclosed various polyimide resins which are reaction products of (a) an aromatic tetracarboxylic dianhydride, such as pyromellitic dianhydride or benzophenonetetracarboxylic dianhydride, with an aromatic diamine and (c) an unsaturated reactive compound, which has unsaturated terminal groups, and is capable of being cured and is useful as a matrix resinous material for prepregs.
The above-mentioned conventional polyimide resins are disadvantageous in that the polyimide resin must be produced from a specific diamine compound, which is very expensive and difficult to obtain; that the resultant polymer exhibits an unsatisfactorily low solubility in an organic solvent and thus is difficult to impregnate in a reinforcing fiber material; that in the preparation of a solution of the polyimide resin, a special organic solvent having a high boiling temperature must be employed; and/or that the resultant polyimide resin exhibits an excessively high melting point, and thus the aimed product must be produced at a very high temperature, which causes a deterioration of the quality of the product.
Japanese Unexamined Patent Publication No. 1-139,632 discloses a terminal-modified aromatic imide oligomer consisting essentially of a oligomerization-imidization reaction product of a biphenyltetracarboxylic dianhydride with an aromatic diamine and an unsaturated monoamine.
The above-mentioned terminal-modified aromatic imide oligomer is disadvantageous in that, when used as a matrix resin for the prepreg, the prepreg containing the terminal-modified aromatic imide oligomer requires a long time for completion of the curing thereof, the resultant cured resin molecules frequently have a number of non-cross-linked terminals thereof, and the resultant cured article has an unsatisfactory mechanical strength.